All guns, therefore, of an unusual size, are not of strength in proportion to a small gun; hence the reason they cannot with safety be charged up to the corresponding scale. Neither are they of the length they should be, if the bore is to be the criterion. It must be remembered that to be charged in proportion, the pressure on the inch should be as many times the pressure on the inch of the small gun, as the one is the number of times larger than the other. If we come exactly to the real state of the case, we doubt much (when taking into consideration the difference of surface) that the pressure on the inch in the large gun is equal even to that on a small gun. The comparison might be carried up to the largest artillery, and I doubt whether it would come up to this scale; as it is well known that the heaviest guns will not throw their projectile as far in proportion as the small gun, because you dare not generate the force required to do it. The same principle is applicable to artillery as to fowling-pieces.
From the above data, I would say, never make duck-guns above seven-eighths in the bore, if you wish them to kill at a great distance; and not less than fifteen or sixteen pounds weight, and full four feet long; because then you can generate strength sufficient. Therefore, instead of the large stanchion-guns being one hundred pounds weight, they should, strictly speaking, be two hundred, and so on. In proof of this I may just mention that, upon repeated experiments, I have ascertained that a double stanchion-gun, with each barrel of the same bore, weight, and length, as a single gun, will kill further than the latter; simply owing to the advantage of the greater weight of the double gun. I have made observations, when trying moderate-sized and shoulder duck-guns on that fine level piece of sand before spoken of, and by tracing the grazing of the shots I have been enabled to pick them up. The large shot from the duck-gun, mostly No. 2, I found scarcely 400 yards from the spot where she was fired; the small shot, five and six, from a fourteen bore, were repeatedly picked up at 350 yards: thus showing that the large gun had not much advantage; but yet making probable many assertions made of killing at seventy, eighty, and sometimes a hundred yards, with a common-sized gun. By this it appears possible; for shot that will fly that distance must kill, if it hit during its flight through the first quarter of such a range; but then, at a single bird, above fifty-five or sixty yards, it is always twenty to one against hitting the object at all; as the pellets begin to separate rapidly at that distance, though their force is still sufficient, and in large flocks is apt to do execution.
The invention of the patent wire cartridge is rather the production of a scientific mind than the production of chance; though the invention of General Shrapnell contains the principle, and the perfection attained is but the extension of that principle: namely, the means of projecting a number of bodies of a similarity in size without subjecting them to an extreme jamming by the lateral expansion, and thus allowing each to travel his allotted distance without any of his companions robbing him of his speed by impact. The great peculiarity of the wire cartridge is, that being less than the bore, and having no bottom wadding, the explosive fluid acts all around, between the sides of the barrel and the net, by what may not inaptly be termed the windage, and the shot are thus expelled by a cushion-like force, which does not jam or compress them in the way it is liable to by a wadding forcing it outwards. Here the net is of use to keep the whole in a mass; but you must not suppose the same would be obtained by a charge of shot, without a wadding below. The net opens, after leaving the muzzle of the gun. The introduction of bone-dust is intended for, and answers the purpose of preventing the grains of shot being mis-shaped by the compression: during their passage up the barrel they form with the bone-dust a comparatively solid body, and keep the pellets from impact, thus allowing them to go forth into the atmosphere beautifully round and uninjured; and, as such, more likely to travel farther and stronger. The latter arrangement possesses all the science, as the net can be dispensed with; for it aids the combination but slightly, and in no case more than a moderate quantity of good paper would do.
The science of this mechanical construction of projectiles is perfectly in keeping with all the established laws of motion, and more particularly good in thus avoiding the necessity of lateral pressure on the sides of the tube of the gun, the upper end having the means of better resisting the column of air in their progress outwards; for there can be no question but this controls and induces the divergence of the shot in leaving the muzzle. One of the old arrangements, often laughed at, I mean the bell muzzle in old guns, intimates that our ancestors possessed some smattering of science; as the relief in the muzzle of a gun has a tendency, by allowing a gradual expansion laterally, to keep the charge of shot better together: for it is quite apparent that any body severely compressed for a certain distance, expands in proportion when free of that restraint; and the consequence is a tendency to fly off at a tangent, as the friction of a crooked barrel induces a ball to fly in a curve contrary to the bend of the barrel.
The extreme relief we find in some old barrels is certainly not required; but still it clearly shows that the principle was understood and acted upon: the very extreme has been produced by ignorance, as certainly as the suggestion was a proof of knowledge on the part of the suggestor; for many think, if a small dose is good for a patient, a large one must be equally so. Like ourselves of the present day, having discovered that fine gunpowder was advantageous, we have carried the principle so far as undoubtedly to overstep the line to which it was beneficial we should advance; thus clearly establishing the truth of the old adage, “One extreme begets another.”
Therefore, in advocating the adoption of gun-barrels of the very essence of iron, I also say, let that part of the tube whose duty is the generating of force be nearly cylindrical, and let there be a gradual expansion of the bore for a few inches in approaching the muzzle, that the restraint of the lateral pressure may not be too rapidly loosened. But yet let that expansion be so graduated that there shall not be an extreme either way—only a scarcely perceptible relief; yet such as will influence and prevent the divergence of the projectiles to a considerable extent.
Blaine says—“A very long barrel is liable to have the force of its discharge lessened by the increase of counter pressure in the greater volume of internal air in a long than in a short barrel.” The column of air in the barrel is unquestionably calculated to lessen the force of the discharge. But I have already shown that this is completely controlled by the system of granulation. Further, he says—“Its force must also suffer by the loss which the elasticity of the propelling gas experiences in its lengthened transit through an extended range of barrel.” He is here supposing an instantaneous generation of force, which cannot possibly happen; and if it did, would be comparatively useless. But he is evidently on the right scent, if he could only follow it up. Again,—“In such cases, it is probable, that the shot, which should leave the mouth of the piece at the instant when the propelling force has gained its maximum, in a long barrel are detained beyond that particular limit of capacity we have pointed out as inherent in each barrel; and which properties, and which quantities of charge, nothing but repeated and varied trials can teach the owner of the gun.”
This is an excellent illustration of the “theory” of the resistance of the column of air in long barrels with very fine quickly-burnt powder; and could he have pointed out the cause, the explanation would have been perfect; as it must be quite apparent to the reader that it is not the length of barrel which is in fault, but a want of a continuous producing force in the powder; for when all the charge is exploded, the maximum has been obtained. This clearly proves that the charge was too small to keep up that maximum, or that the grain of the powder was too fine, and thus too quickly expended. There is no discrepancy between the fact of long barrels being preferable half a century ago, and short ones now; for it is in the improvement of gunpowder burning in half the time now that it did then, and leaves the question of length of barrel precisely where it has ever been. You may have any length you like in moderation, if you suit the grain of powder to it.
I am quite satisfied to steer between extremes; avoiding alike too small a charge of projectiles and too wide a calibre with too heavy a charge of the former, and preferring a size of bore that gives, under all circumstances, the greatest range with the least amount of explosive material; which neither requires that to be too fine a grain, nor too coarse: namely, a bore of fifteen and two feet six inches long. Under all the above circumstances combined, this size will long hold a position in the front rank of sporting guns.
The Belgians have long been, and still are, our principal competitors in supplying those parts of the world which do not rank gun manufacturing among their staple trade. The cost of labour being small, they have great facilities for producing cheap material; and the extent to which they tempt the eye of those inexperienced in gunnery is quite obvious to the world; but excepting the cheapness of the lower grade of guns, the Belgian products are not at all to be placed on an equality with the well made English manufacture.